The present invention relates to a lockset having a shuttling throw member, and particularly to a lockset including a shuttling throw member connecting a lock core to a locking-unlocking mechanism in the lockset. More particularly, the present invention relates to a lockset having a key-operated lock core and a shuttling throw member that connects the lock core to the locking-unlocking mechanism in the lockset only when the key is inserted into the lock core and rotated a predetermined amount.
Locksets are well known as shown, for example, in U.S. Pat. Nos. 3,955,387 to Best, et al.; 4,424,691 and 4,437,695 to Foshee; and 4,262,507 to Flack et al. A lockset is a lockable unit that connects a door handle to a retractable latch bolt mounted in a door so that the door handle can be turned to retract the latch bolt and unlatch the door when the lockset is unlocked. Once the lockset is locked, the latch bolt cannot be retracted to unlatch the door by turning the door handle. Typically, a lockset is mounted in a lockset-receiving aperture provided in a door in a location adjacent to the door handle and latch bolt.
A lockset typically includes a locking-unlocking mechanism for locking and unlocking the lockset. When the lockset is locked, latch bolt retraction is prevented to lock the door in a closed position. When the lockset is unlocked, the latch bolt may be retracted to allow the door to open upon rotation of the door handle.
Everyone has operated a locking-unlocking mechanism in a lockset by inserting an operating key into a lock core mounted in a door handle and turning the operating key. A lock core typically includes a rotatable key plug formed to include a keyway sized to receive the operating key. A throw member is usually provided to transmit rotation of the key plug (caused by turning of an operating key) in the lock core to a locking-unlocking mechanism provided in the lockset to control movement of a locking lug relative to a retractable latch bolt. Usually, a person is able to operate the locking-unlocking mechanism in the lockset simply by turning an operating key enough to rotate the key plug, the throw member connected to the key plug, and the locking-unlocking mechanism.
Consumers would appreciate a lockset having a throw member that disengages the locking-unlocking mechanism when the operating key is removed from the lock core. A throw member that could "shuttle" automatically to a position disengaging the locking-unlocking mechanism in a lockset would increase the security of the lockset, especially when excessive torque is applied to a door handle of a locked lockset in an attempt to "break" the lockset.
According to the present invention, a throw member is provided for use in a lockset. The lockset includes a rotatable door handle, a lock core, and a locking-unlocking mechanism for locking and unlocking the lockset. The throw member is configured and controlled to connect the lock core to the locking-unlocking mechanism when an operating key is inserted into a keyway provided in the lock core and rotated a predetermined amount. The locking-unlocking mechanism is operated by rotating the operating key in the lock core.
The throw member is mounted in the lockset for rotation about an axis of rotation and for reciprocation along the axis of rotation so that it can shuttle back and forth between an enabled position engaging the locking-unlocking mechanism and a disabled position disengaging the locking-unlocking mechanism. The throw member includes a blade extending away from the door handle and a mechanism for shuttling the blade axially along the axis of rotation relative to the door handle between its enabled and disabled positions. The shuttling is provided so that when the operating key is inserted into the lock core and rotated a predetermined amount, the blade on the throw member is moved to engage and rotate the locking-unlocking mechanism so as to lock or unlock the lockset.
During removal of the key from the lock core, the blade on the throw member is moved to its disabled position to disengage the locking-unlocking mechanism. Disengaging the throw member from the locking-unlocking mechanism when the operating key is removed from the lock core prevents the blade of the throw member from shearing off during an overtorque attack on the lockset. Further, the disengaging feature helps keep a locked lockset in a locked position during an overtorque attack on the lockset.
In preferred embodiments the throw member includes the blade, a pair of spaced-apart drive prongs, and a circular disk or body portion between the blade and the drive prongs. The blade projects away from one side of the body portion toward the locking-unlocking mechanism and the pair of spaced-apart drive prongs project away from the other side of the body portion and engage a key plug mounted for rotation in the lock core and configured to include a keyway.
A camming mechanism is provided in the lockset to shuttle the throw member axially along the axis of rotation as the throw member is rotated by rotation of the operating key and the rotatable key plug in the lock core about the axis of rotation. One part of the camming mechanism is formed in the circular body portion included in the rotatable and reciprocable throw member and another part of the camming mechanism is mounted in a fixed position in the lockset to engage the circular body portion as it rotates.
The camming mechanism functions to move the throw member axially along the axis of rotation between a disabled position disengaging the locking-unlocking mechanism and an enabled position engaging the locking-unlocking mechanism. More specifically, the throw member is shuttled into the enabled position engaging the locking-unlocking mechanism by the camming mechanism whenever the operating key is inserted into the keyway formed in the rotatable key plug mounted in the lock core and turned a predetermined amount. Whenever the operating key is removed from the lock core, the throw member is shuttled by the camming mechanism into the disabled position disengaging the locking-unlocking mechanism.
In preferred embodiments of the invention, the throw member includes an outer perimeter edge on the circular body portion and a serpentine channel formed in the circular body portion to extend around the outer perimeter edge. A pin is fixed relative to the door handle and extends into the serpentine channel. The serpentine channel and the pin cooperate to define the camming mechanism. As the throw member is rotated in response to rotation of the operating key within the lock core, the pin cams the throw member to move the throw member axially along the axis of rotation.
Additional objects, features, and advantages of the invention will become apparent to those skilled in the art upon consideration of the following detailed description of preferred embodiments exemplifying the best mode of carrying out the invention as presently perceived.